This is out of the evox.ini? In that case you will only see your HDD temp in the origional skin. BTW I just cut and pasted from the earlier post of what it should look like as an example. Paste this over those first two lines, and delete the example line I gave you:
Text = 30,37,0.5,0x000000,0,"<Time><CrLf>MB Temp <Temp1><CrLf>CPU <Temp2><CrLf>HDD <Temp3>"
Text = 28,39,0.5,0x808080,0,"<Time><CrLf>MB Temp <Temp1><CrLf>CPU <Temp2><CrLf>HDD <Temp3>"
This will list HDD in the corner with the other temps. This should work as you said the HDD temp showed a reading in the settings.
REMEMBER:This will only show the temp in your origional skin, you must add it to your other skins if you want the reading to show up there.